This application claims the priority of German patent 198 42 723.9, filed Sep. 18, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a chain drive for internal-combustion engines, particularly for driving one or several camshafts, secondary shafts, or the like, on such engines, a tensioner blade or sliding blade being applied to the slack side and to the load side of a chain of the chain drive.
In a chain drive known from German Patent Document DE 36 23 903 C1, a tensioner blade interacts with a load side of the chain by way of a tensioning device. Another blade is constructed as a chain guide for a load side and is fixed with respect to its position.
A comparable construction is disclosed in German Patent Document DE 34 17 100 A1, in which, for compensating manufacturing tolerances of the crankcase, blades of the chain drive are disposed in a floating manner transversely to the longitudinal direction of the chain.
German Patent Document DE 37 06 136 C1 relates to a chain tensioner consisting of a plastic material for guiding and tensioning a chain. This tensioner has a slide coating made of a wear-resistant material and a support made of a bending-resistant material, such a polyamide.
None of the above-mentioned references supplies information as to how normal component tolerances of the chain drive can be compensated with acceptable expenditures particularly with respect to the distance between the sprocket wheels and/or the chain.
It is therefore an object of the invention to provide blades, particularly on the guiding blade and/or the tensioner blade of the chain drive, that can compensate for component tolerances caused either by manufacturing or wear influences without any problem.
This and other objects have been achieved according to the present invention, by providing a chain drive for internal-combustion engines, particularly for driving one or several camshafts, secondary shafts, or the like, on such engines, a tensioner blade or sliding blade being applied to the loose end and to the load end of a chain of the chain drive, characterized in that the tensioner blade and the sliding blade are each disposed in an articulated manner on a first side by means of bolts and one adjusting device respectively is applied to a second side of these blades.
This and other objects have been achieved according to the present invention, by providing a chain drive for an internal-combustion engine, comprising: a chain; a tensioner blade engaging a loose side of said chain; a sliding blade engaging a load side of said chain; said tensioner blade and said sliding blade each being disposed in an articulated manner at a first end; and adjusting devices being applied to second ends of said tensioner blade and said sliding blade, respectively.
The principal advantages achieved by the invention are that, by way of the two adjusting devices, on the one hand, measurement deviations from the design position can be compensated in a simple manner and, on the other hand, a targeted tensioning function is ensured on the chain. In this case, a preadjustment for the reduction of component tolerances of the chain drive takes place by way of the fixing device, whereas the tensioning device essentially covers the actual tensioning range. In the design of the tensioning device and the fixing device, proven principles of machine construction can be used. The receiving section of the fixing device simultaneously promotes the guiding of the sliding blade in its transverse direction.
A spatially favorable construction and bearing of the two blades is achieved in that the bolts are situated outside the chain drive. This also applies to the arrangement of the fixing device; that is, on the chain between the sprocket wheels. The shape of the blades is in each case such that it is composed of oppositely oriented curves and is particularly suitable for a chain drive with two chain sprockets because it can easily be adapted to the given space conditions. The blades finally consist of a suitable plastic material, which has a cost and weight reducing effect.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.